The present invention relates to the manufacture of building materials, and more specifically to methods of producing mineral binders and apparatus embodying same.
Widely known nowadays is a thermal method of producing mineral binders, Portland cement in particular, wherein one or another mineral binder is made by sintering a certain stock in a kiln and grounding the clinker so obtained. The main disadvantages of this method are a protracted time period for the process which can last at least a few hours and considerable fuel requirements for maintaining the temperature in the kiln at a sufficiently high point which reaches its maximum between 1400.degree. and 1500.degree. C.
Disclosed quite recently has been a method of producing mineral binders, Portland cement in particular, by exposing a corresponding stock to an ionizing irradiation, a beam of electrons in particular. As it will be noted from the publication, the method is embodied under the conditions of a high vacuum while the material travels down slanting surfaces due to gravity at right angles to the beam of electrons without being mixed.
The advantage of this latter method compared with the thermal one is that it requires no fuel. Yet, the new method suffers from disadvantages of its own which are a non-uniform treatment of the material and the inability to utilize all the energy of electrons.
The known apparatus for producing mineral binders by means of this latter method consists of an air-tight chamber with a feeding device at the top and a discharging arrangement at the bottom. Disposed in the chamber are two continuous tilted troughs, moving down thereon, due to gravity, is the material treated, i.e. the stock. Provided above the troughs is a source of ionizing irradiation, usually a source of electrons emitted in a beam which is directed mainly at right angles to the material treated, i.e., ionized.
The main disadvantage of this apparatus we perceive is that it lacks the mixing of the material, is highly sensitive to the depth of layer and the apparatus is exposed to the destructive action of the ionizing irradiation.
Also known are apparatus for processing a variety of materials by means of ionizing irradiation, each consisting also of an air-tight chamber disposed wherein there is a horizontal conveyor which assures the travelling of the material through the chamber. A source emitting a beam of accelerated electrons is disposed under the conveyor so that the beam of electrons is directed at right angles to the working surface of the conveyor.
The main disadvantage of said apparatus is that the material is treated non-uniformly.